[18a-PB01-1~25] 12.5 Organic and hybrid solar cells

▲ [18a-PB01-18] Improvement of SnO₂ Electron Transport Layer formed by ALD for High-Efficiency Hybrid Perovskite Solar Cells

〇(M2)sanggeun Cho¹, Ho Dong Son¹, Sang Ho Won¹, Tae Woong Kim¹ (1.Konkuk University)

Keywords:perovskite solar cell, electron transporting layer, atomic layer deposition

Hybrid perovskites have attracted great attention as a next-generation renewable energy material and a solar cell adopting the hybrid perovskite has achieved 25.7% of power conversion efficiency (PCE), recently. The electron transporting layer (ETL) is a critical element in solar cells and, therefore, various fabrication methods of the ETL have been studied for the development of high-efficiency hybrid perovskite solar cells (PSCs). Atomic layer deposition (ALD) is a method that can fabricate ETL compactly and reduce defects such as pinholes. However, despite the above merits, the ALD has not achieved high PCE compared to other methods such as chemical bath deposition (CBD). The unsatisfactory results of the ALD ETL may be because the optimization of the ALD process has not been completed yet, rather than problems caused by the fundamental principle of the ALD deposition. In this study, we introduce a new ALD process for SnO₂ ETL obtained by controlling O₃ reactant concentration and by applying a post-treatment process using KCl.
The concentration of the O₃ reactant was controlled from 160 to 220g/cm³ during the growth of the SnO₂ ETL (precursor: TDMASn, reactant: O₃). Then, 74.55g/mol KCl was spin-coated on ALD SnO₂ thin films and annealed at 100°C for 10 min. The PSC used in this study is composed of FTO Glass/SnO₂/KCl/CH₃NH₃PbI₃/Spiro-OMeTAD/Ag layers.
Consequently, we achieved PCE of over 17% with SnO₂ ETL of 190g/cm³ O₃ concentration and KCl post-treatment. The above is not the final result and the optimization of the ALD process to develop highly efficient PSCs via the enhanced photovoltaic parameters is still in progress.